The Effects of Summer Heat on a Hydraulic Fluid

As the summer heat rises in large facilities, businesses using fluid power systems must take steps to ensure their fluid power equipment is equipped to handle the high temperatures.

While cold weather is responsible for some liquid power system failures, hot weather has its own drawbacks.

By understanding how heat affects your fluid power system and preparing your fluid power systems for the summer season, you reduce risks to your hydraulic equipment that can lead to costly downtime and increased maintenance demands. In this article, you will find preparation information and tips to help you understand and mitigate the effects of heat on Rexroth valve hydraulic fluid.

It is important to understand viscosity.

Be sure to read and understand the viscosity chart for your oil to understand how oil viscosity changes at different operating temperatures.

The viscosity of petroleum-based hydraulic oil decreases with increasing temperature. This reduces its ability to reduce heat and partial wear friction.

The low viscosity of the oil causes a loss of the strength of the lubricating film. If the load on the hydraulic system remains the same, but higher operating temperatures reduce the oil viscosity below what your equipment needs, the chances of friction, wear and adhesive wear increase.

Stay cool by controlling the temperature.

One way to help your hydraulic fluid system adapt to hot weather is to monitor the operating oil temperature. This means you need to have enough cooling cycles before the warmer weather arrives, rather than waiting for the warm season to start.

One way to prevent temperatures in your hydraulic power system from rising further is to make sure you are using the correct oil in the system.

Few hydraulic systems have an overall efficiency of more than 85-90%, and lower-efficiency systems generate more heat. Therefore, any hydraulic system with low efficiency constantly generates heat and may require heat exchangers.

If you use heat exchangers with your systems, make sure they are not too small for the job. This can exacerbate your heat problem when your devices experience higher ambient temperatures.

Humidity: a sticky problem

Depending on your location, high temperatures can also cause increased humidity, which can lead to contamination of the water in your Rexroth Motors.

Water in hydraulic oil can cause surface corrosion and increase wear on the metal parts of the system. Water can also reduce oil viscosity, contributing to systems overheating and the wear that accompanies this condition.

Before wet weather hits, perform oil analysis on all systems to check for water content. Replace air sump in hydraulic tank with desiccant breathers. This will help evaporate or absorb any water that has contaminated the hydraulic system.

Cool head prevails when the heat is turned on

Hot weather presents challenges for liquid energy systems, just like winter. Careful management of oil temperature and viscosity, as well as paying attention to whether water contamination is caused by high humidity, are important to keeping the system running smoothly.

It's also important to pay attention to how hot the system needs to run, as extreme temperatures break down lubricating oil and can damage metal parts.

These considerations are key to avoiding the cost of replacing parts and shutting down systems for repairs.

As with many preventable situations, an ounce of prevention, or in this case, preparation, is worth more than a pound of cure!